As oral administration of the EP2 antagonist and oral delivery of the EP4 antagonist ONO-AE3-208 significantly reduced tumor burden and DSS-induced colitis, respectively, when given during disease development (48, 56), we hypothesized that Hpb exacerbation of CAC in mice fed a high ω-6:ω-3 ratio diet may be due to increased EP2/4-dependent signaling. This evidence concerns the gene PTGER4 and neoplasm.